The present invention relates to a procedure for the longitudinal orientation of wood chips and the like, particularly during the production of OSB boards (Oriented Strandboard). Discs rotating in the direction as chip flow are positioned above a moving base that receives the chips. The discs are arranged on shafts at corresponding distances from the moving base, and the discs are equidistant from one another.
A device for production of a particleboard containing oriented wood particles of varying dimensions is known from West German Pat. No. 11 74 058 in which a number of orientation elements, movable in relation to one another and connected with a drive device, are arranged on a plane inclined to the horizontal. The orientation elements are generally parallel to one another, forming narrow orientation passages. The width of these passages and the distance between the lower edges of the orientation elements and the surface on which the layer of chips is formed are only slightly greater than the average length of the wood particles. Due to the movements of the orientation elements relative to one another and the distance between the elements, such a device for longitudinal orientation of chips is not suitable for longitudinal orientation of chips during the production of OSB boards. The distance between the orientation elements allows the chips, which are to be longitudinally oriented, to assume positions at right angles to the longitudinal orientation, since the longest guidance of the chips to be longitudinally oriented generally occurs only along the common chord of two adjacent elements and the adjacent elements are attached to two different and sequentially arranged shafts. Since the orientation elements located on other shafts affect a positioning of chips to be longitudinally oriented over a distance which is only slightly greater than the average lengths of the wood particles, the major portion of the chips to be longitudinally oriented does not fall through these orientation elements in a properly oriented manner. Since they are not influenced by the orientation elements, they are generally deposited onto the receiving base in an arbitrary and unoriented manner. Also, since the orientation elements on one shaft are located at a distance from one another which is at least double the average length of the wood particles, many of the chips do not fall through the elements in a properly oriented manner.
There has been no lack of attempts to eliminate the shortcomings with respect to chip orientation. For example, devices are known in which stationary metal grids are arranged in the transport direction and extended below the shafts carrying the orientation discs whereby the individual discs also extend into these grids. Attempts have been made to force a longitudinal orientation of the chips by means of spiked devices arranged on the discs. However, the result is a device in which the passage width in the unaffected area of the grid is only slightly greater than half the average length of the wcod particles, and the width of each passage through the grid is decreased at the entrance area to the grid, namely by the intruding discs. Moreover, in cases of extreme errors in the chip dimensions or if splinter material is present, blockages may occur.
Orientation problems increase with increasing chip dimensions and reach their maximum when strands are to be oriented. The strands to be oriented consist of wood particles with dimensions which do not correspond to those chip dimensions defined for production of normal particleboards. In this case, wood particles (strands) are to be oriented which are preferably 70 mm long, 10-30 mm wide and 0.5-1 mm thick. Furthermore, it is impossible to avoid splinters and extreme overdimensions in this type of wood processing, unless additional and costly sorting devices and devices for after-treatment are provided.